Slub fabric is made from yarn with planned thick and thin places, giving a textured, casual look. How slub yarn is made, what it is used for, slub vs heather, and what our records show about its weight and shrinkage.
At a glance
Thick & thinplanned in the yarn
130 → 148GSM finished → washed
8.5%length shrinkage
906slub and yarn-dyed entries
Slub fabric is fabric knitted or woven from slub yarn: yarn with thick and thin places spun into it on purpose. The thick places, called slubs, show as short, slightly raised and often slightly darker dashes across the fabric, giving it an uneven, textured, natural look. Slub cotton jersey is popular for casual T-shirts, henleys, tank tops and summer tops, because it looks relaxed and lived-in rather than smooth and flat.
This guide explains what slub yarn is and how it is made, what slub fabric is used for, slub versus heather and plain jersey, and how slub behaves in dyeing and finishing, with figures from our development records.
What is slub yarn?
A normal yarn is spun as evenly as possible. Slub yarn is spun to be uneven: during spinning, the drafting speed is changed in a programmed pattern so that, for short lengths, more fibre goes into the yarn. Each of those lengths becomes a slub, thicker and softer than the yarn around it. The spinner controls the slub length, thickness and spacing, so a slub can be subtle or bold.
Slubs in fabric are a design, not a fault. A thick place in a normal yarn is a yarn defect; in slub yarn it is planned and repeated.
What is slub fabric used for?
- Slub T-shirts and henleys: the most common use, usually in cotton single jersey.
- Tank tops and summer tops: lightweight slub jersey looks airy and casual.
- Linen-look fabrics: slub cotton or viscose imitates the natural irregularity of linen.
- Home textiles: curtains, cushion covers and upholstery with a woven slub texture.
Slub vs heather vs plain jersey
| Fabric | Where the effect comes from | Look |
|---|---|---|
| Plain jersey | Even yarn | Smooth, uniform |
| Slub jersey | Thick and thin places in the yarn | Textured dashes, irregular |
| Heather (melange) jersey | Yarn spun from dyed and undyed fibre | Flecked, mixed colour, smooth |
Slub and heather can also be combined: a slub yarn spun from mixed fibre. For heather, see what is heather fabric.
How slub fabric behaves in dyeing and finishing
Slub single jersey is knitted on the same machines as plain jersey, usually on coarser gauges in our register, and is either piece dyed as fabric or knitted from yarn that was dyed first. Slubs bring two practical problems:
- Weight varies with the slubs. The thick places add fibre unevenly, so GSM varies more along the length than in plain jersey.
- Length is stretched in finishing. Slub fabric tends to leave the stenter with length still pulled in, then relaxes and gains weight when washed.
In our records, a 32/1 slub single jersey ordered at 150 GSM finished at a median 130 GSM but rose to 148 GSM after the wash test, with about 8.5% length shrinkage. That pattern, light off the machine and heavier after washing, is why slub needs extra relaxation and compaction. The full development details are in the slub and yarn-dyed jersey development guide, from 906 entries for yarn-dyed, slub, design and heather jersey in our register.
Common mistake: rejecting slub fabric for “uneven shade”. Slubs often look slightly darker, because there is more fibre in a thick place to hold dye. That is the character of the fabric. Approve slub against a slub standard, not against plain jersey.
Does slub fabric shrink?
Slub cotton jersey can shrink more than plain jersey if it has not been relaxed properly, because its length is often stretched in finishing. In our records 32/1 slub shrank about 8.5% in length against a median of 5% for cotton single jersey. Buy from makers that pre-shrink, wash cool and avoid hot tumble drying. See what pre-shrunk means.
How to care for slub fabric
- Wash at 30°C, inside out, to protect the raised slubs from rubbing.
- Avoid hot tumble drying; dry flat or on a line.
- Iron on the reverse, on a medium setting.
Worked example. A brand orders a 150 GSM slub T-shirt fabric. If the mill finishes it to 150 GSM straight off the stenter, it may be heavy and shorter after the buyer’s wash test. Finishing a little light, relaxing it properly and checking a washed sample, as our records suggest, gives a far better chance of passing both GSM and shrinkage.
Summary
- Slub fabric is made from slub yarn with planned thick and thin places.
- Slubs give a textured, casual, linen-like look; they are a design, not a fault.
- Slub differs from heather, which gets its effect from mixed-colour fibre.
- In our records 32/1 slub finished light (130 vs 150 GSM) and shrank about 8.5% in length.
- Wash cool, inside out, and avoid hot drying.
Colour instead of texture: for yarn that changes colour along its length rather than thickness, see what is space dyed fabric.
Questions
What is slub fabric?
Fabric knitted or woven from slub yarn, which has thick and thin places spun in on purpose. The slubs show as short, textured dashes that give a casual, natural look.
What is slub fabric used for?
Mostly T-shirts, henleys and summer tops in cotton jersey, plus linen-look fabrics and home textiles.
Is slub fabric good quality?
Yes. Slubs are a planned design, not a fault. Quality depends on the yarn, the knitting and how well the fabric was relaxed and pre-shrunk.
What is the difference between slub and heather?
Slub texture comes from thick and thin places in the yarn; heather comes from yarn spun from a mix of dyed and undyed fibre, giving a flecked colour.
Does slub fabric shrink?
It can shrink more than plain jersey if not relaxed properly. In our records a 32/1 slub jersey shrank about 8.5% in length after the wash test.
Textile engineer with 14+ years in dyeing and fabric development. He writes every guide on Dyeing Solution from real production work. Full profile